Bi-annual US dollars 1987-06-30 68 1987-12-31 66 1988-06-30 67 1988-12-31 108 1989-06-30 85 1989-12-31 111 1990-06-30 77 1990-12-31 66 1991-06-30 83 1991-12-31 82 1992-06-30 61 1992-12-31 62 1993-06-30 33 1993-12-31 40 1994-06-30 48 1994-12-31 58 1995-06-30 37 1995-12-31 31 1996-06-30 61 1996-12-31 120 1997-06-30 170 1997-12-31 16 1998-06-30 47 1998-12-31 50 1999-06-30 19